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Discussion Starter · #1 ·
In doing dyno runs to see gains made from mods, I have been told that you need to disconect battery for 24 hours before doing run after base line run to get full affect of mod. I have also been told that you need to run the truck for 300 miles between runs to let the computer learn the new curves. How much of this is true, and how much is bunk?
 

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I never did a dyno run on my truck. when I did the exaust I didnt disconect the battery, i took it for a test drive and felt a little power but not enough to satisfy me. then I started to read and figured out the battery trick, I disconnected it for 2 hours. when I went for a ride this time and it was warm again I just hammered it while rolling at about 20-25 mph, and both tires lit up all through first and second gear till I let up. The truck had never lit them up like that while rolling before, and I only had about 5 miles on the reset ECU! the computers in cars now learn very quickly, they will change the way it shifts depending on who is driving the truck and how they want to drive it in a matter of minutes. otherwise it would be pointless to change stuff like that if it took 300 miles to do. considering even if you are the only one to drive it you still unconcously push your foot down different every day your in it(depending on mood!). Its the same with all other curves in the computers data, it changes the timing and fuel curves all the time depending on temp. and humidity outside.
 

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Discussion Starter · #3 ·
JetTech, where ya at man? I was looking for your input here along with other experianced dyno guys!
 

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The subject of disconnecting the battery is a very common one and I've never really been able to prove it helps. For example when I installed the straight pipes on my truck, (remember my SES light coming on), it took the computer 3 weeks to learn how to adapt to these new pipes before it shut the light off. And of course I tried disconnecting the battery for 24 hours and that didn't work.

It takes a while for the computer to establish a long term fuel trim, it's not something it learns right after the battery is reconnected and the engine is first started. When the battery is disconnected for however long, the computer reverts back to basic programmed settings, then after it's run for a few weeks, depending on how much you drive, it will learn the new settings.

If I was you I wouldn't bother disconnecting the battery, just run the new exhaust for several weeks before you go and have it dynoed again. That way you'll be sure that your computer has learned it's new settings for the mod you have done.
 

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Discussion Starter · #5 ·
If I was you I wouldn't bother disconnecting the battery, just run the new exhaust for several weeks before you go and have it dynoed again. That way you'll be sure that your computer has learned it's new settings for the mod you have done.
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So if I understand you correctly. To properly do this test review, once I get the base dyno done, and install the exhaust, I must run the truck a few weeks (or 300 miles?) in order to get proper gain readings? Then do the same once intake is installed? Is there any way I can tell for sure ECU has adjusted to the mod before follow up dyno run?
 

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yes, that would ensure your short and long term fuel trim settings have adapted to the mods.

I do want to clarify though, in case anyone is wondering, that you WILL see a gain/loss on a dyno immediately after a mod is done. BUT.....the true gain/loss will not be realized until all fuel trim settings have adapted.

Your using the most accurate dyno for these tests so you might as well take the time to let the computer adapt after the mods are accomplished.
 

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Discussion Starter · #7 ·
Your using the most accurate dyno for these tests so you might as well take the time to let the computer adapt after the mods are accomplished.
I agree, my main goal in doing this test/review is to provide REAL info. I hope beyond hope that the mods do great things for our truck, but I want to be sure any info I give is 100% correct and unbiased.
 

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SMOKEDYA2 said:
the computers in cars now learn very quickly, they will change the way it shifts depending on who is driving the truck and how they want to drive it in a matter of minutes. otherwise it would be pointless to change stuff like that if it took 300 miles to do. considering even if you are the only one to drive it you still unconcously push your foot down different every day your in it(depending on mood!). Its the same with all other curves in the computers data, it changes the timing and fuel curves all the time depending on temp. and humidity outside.
I also wanted to comment on smokedyas post. When considering shift adaption that is a whole different programmed set of variables that are more so looking at throttle position and rpm. While it's true, this is an almost intantaneous adaption, it's not the same as fuel curve and trim adaptions, hence the reason it takes longer for modifications to "settle in".
 

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Discussion Starter · #9 ·
I also wanted to comment on smokedyas post. When considering shift adaption that is a whole different programmed set of variables that are more so looking at throttle position and rpm. While it's true, this is an almost intantaneous adaption, it's not the same as fuel curve and trim adaptions, hence the reason it takes longer for modifications to "settle in".
I just LOVE it when you talk all that technical stuff! I'm warm and fuzzy all over now! :oops:
 

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sorry.... :oops: Here's perhaps a better way to explain this whole thing.

When you disconnect your battery, your computer reverts back to the factory default settings and will have to "learn" your mods from those settings.

Now if you don't disconnect your battery, your computer will still adapt to the mod the same way it did when you unhooked it. Now is it quicker to learn when you disconnect the battery??? My tests with my straight pipes just proved the answer to that one, of which was a resounding NO...

Would it speed up the learning process in other makes of vehicles??? I have no idea because I haven't done any testing like this on other makes before, but I guess it's possible.

Is that better???
 

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Discussion Starter · #11 ·
Thanks JT, great response!
 

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so they tell us to unhook the battery only to prevent accidental shock, right
 

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SMOKEDYA2 said:
so they tell us to unhook the battery only to prevent accidental shock, right
not really :lol: I'm convinced this is more of an "industry standard" thing than a Titan thing. You and I will have to compare ECU part numbers some day. I have no logical explanation as to why your truck will spin the heck out of the tires when most don't. I do know there are about a dozen different ECU part numbers that Nissan uses in the Titans, you may be the lucky recipient of a scorcher ECU, or "freak of nature" as m4ck likes to call them :lol:
 

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I'm not sure which number your looking for but I found a few on a sticker. just to make sure, the ECU is right behind the battery right. that being said I found 3 different groups of #'s. a black box with white letters had 1353 in it. another box with black letters had 891310-8R in it. also Slot 108 written on sticker in another spot.
do these help? mabye my seat of pants feel was wrong but the tire spinning was never that drastic before, especially while rolling.
 

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My truck is always "quick" by truck standards, but there are days when it feels like someone took a whip to it when I mash the go pedal, on those days it will break the rear loose from a roll(with vdc off) and keep them spinning through second and into third.
 
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